William O'Brien State Park

Trip Advisor

Key Information

Contact Info

(651) 539-4980


16821 O Brien Trail N, Marine on St Croix, MN 55047, United States

Opening Hours

8:00 AM to 10:00 PM


Park permits are $35 per year, $26 for a second vehicle, $12 for a handicapped person, or $7 per day. Camping fees are not included.


Introduction of William O’Brien Park

William O’Brien State Park is a 1,520-acre (6.2 km2) Minnesota state park located along the St. Croix River. Its trails wind through rolling glacial moraine, riparian zones, restored oak savanna, wooded areas, and bogs. It is a popular destination for birdwatching, picnics, camping, cross-country skiing, canoeing, fishing, and other outdoor recreational activities.
The park is about two miles north of Marine, Minnesota, on the island of St. Croix.

William O’brien State Park Camping

Riverway Camp

You’ll find everything you need for an enjoyable RV stay at William O’Brien State Park. Between the two campgrounds, there are 114 total sites where you can park your big rig or campervan, with the majority of them accommodating RVs up to 60 feet in length. You can also choose between cool and shaded areas and open and spacious areas. The Riverway Campground has 30-amp electric hookups, but that’s not all. During your stay, you will have access to flush toilets, showers, and a dump station to meet all of your needs. The toilets and showers are wheelchair accessible, and three ADA-accessible campsites are conveniently located near the bathrooms. However, keep in mind that this campground is only open during the peak season, from mid-April to mid-October.

Savanna Camp

This is the campground to stay at if you want to bring your campervan during the off-season because it is open all year. Another great feature is the availability of 50-amp electric hookups. Just keep in mind that if you visit during the off-season, the flush toilets, showers, and dump station will be unavailable. However, you are welcome to use the nearby vault toilets or the visitor center bathrooms.

William O'Brien State Park river view
CC: Social Channel of Park


William O’brien Park Activities

Fishing at William Park

Fishing can be a very relaxing activity, but it does not have to be done during peak season. Theregültig reason actualgültig cheval picturesgültig cheval privategültig cheval Dongültig cheval goldgültig cheval Dongültig cheval mattergültig cheval notegültig chevalgültig cheval mattergültig cheval cheval cheval Don’t worry if you forgot to pack your fishing pole or tackle box in your camper or trailer. The park will lend you some items so that you do not miss out. Simply contact the park office and they will take care of you.

Hiking on park trails

There is a trail for everyone, whether you are an experienced hiker or just starting out. 12 miles of trails allow you to explore shaded woodlands as well as marshy wetlands. You may even see some incredible wildlife along the way. The Riverside Trail, which has informative signs along the way and is even ADA-accessible, is a great place to start exploring. It’s only a mile and a half long, and there are rest stops along the way.

Picnicking at Wiliam O’Brien Park

There are two picnic shelters in the park, one near the main picnic area and one near the beach area. You’ll get to enjoy some amazing park scenery wherever you decide to sit and eat your meal. These shelters are wheelchair accessible and have electricity and a fireplace. You can reserve one of these picnic shelters for your group by contacting the park office, and they will handle the rest.

Water Sports

Visitors to Lake Alice Beach can either dive right in or simply cool off. Some people prefer to simply sunbathe on the beach. Because of the currents, swimming is not permitted in the river. Air mattresses and flotation devices are only permitted inside the roped area for safety reasons.

Kayaking and Canoeing in William State Park

The St. Croix River is an excellent place to canoe or kayak. Nothing beats wading down a gentle river in the sunshine. But just because you didn’t bring your own canoe or kayak doesn’t mean you have to miss out on the fun. You can rent one of these boats from the park as long as you visit between mid-May and mid-October, which is the best time to visit.


To help control the deer population, special hunts have been scheduled in Minnesota state parks. The Department of Natural Resources maintains an up-to-date list of park accessibility as well as information about hunting regulations, dates, and limits on their website.

Trail Activities in the Winter

The fact that there is snow on the ground does not mean that the fun has to come to an end. Many of the trails become available for cross-country skiing, snowshoeing, and skate-skiing during the off-season. There are 12 miles of groomed trails available for all levels of skiing, ranging from easy to difficult.

William O’Brien State Park Location

The drive to William O’Brien State Park, which is located on the St. Croix River in Minnesota, is not only easy, but also enjoyable, with plenty of scenery to look at along the way. This park is ideal for RVs and campervans of all sizes. Most drive-in campsites can accommodate vehicles up to 60 feet long, and the roads leading there are wide enough for you to ride comfortably without encountering any issues.

There are also plenty of parking lots throughout the park for your vehicle. Parking is available at the campgrounds, Day Use Area, Interpretive Center, and at the trailheads for many of the trails. Of course, during peak season, parking spaces are more likely to be taken. During the off-season, however, you should have no trouble parking your RV almost anywhere.

Public Transport

Public transport is not available for William O’Brien State Park.

The Area’s Nature

The St. Croix River floodplain, oak-hickory forests, scattered white pine areas, marshes, oak savanna, upland prairie, and rolling meadows provide habitat for a variety of wildlife populations. Wildflowers add a splash of colour to the spring woods and summer fields.
Sandstone outcrops formed by inland seas millions of years ago can be found along the St. Croix River. Glacial activity played a significant role in the formation of the picturesque valley. As the massive glaciers lumbered south, they scoured the sandstone and deposited various sizes of soil and rocks. The tremendous volume of released water cut through the soft sandstone, creating the St. Croix River and landscaping the wide, boulder-strewn valley as large masses of ice melted.

Racoons, minks, beavers, and woodchucks are common. White-tail deer and fox thrive in upland meadows and wooded areas. Woodpeckers, bluebirds, orioles, herons, raptors, and a variety of warblers are frequently seen by birdwatchers.


The Dakota and Ojibwe Indians made use of the valley’s resources, which included fur-bearing animals, wild game, and useful plants. European trappers arrived in the 1600s to participate in the lucrative fur trade. Later, lumberjacks began to harvest the white pine stands. Sawmills began to sprout up along the St. Croix River, and the industry thrived until the valley was cleared of white pine in the mid-1800s. William O’Brien, a lumber baron, purchased much of the land that had previously been owned by the lumber companies. In memory of her father, his daughter donated 180 acres to be developed as a state park in 1947. Other privately owned parcels of land have been added to the park over the years, bringing the total area to 1,520 acres.


William O'Brien State Park Photos

William O'Brien State Park Map